Gas producer



Sept. 15, 1931. F. B. CROSBY 1,822,885

GAS PRODUCER Filed April 29. 1929 5 Sheets-Sheet 2 Sept. 15, 1931. F. B. CROSBY 1,822,885.

GAS PRODUCER Filed A ril 29. 1929 5 Sheets-Sheet 3 19 v u fay I Sept. 15,1931. F. B. @0 5? 1,822,885

' GAS [PRODUCER Filed Aiaril 29'. 19 5 Sheets-Sheet 4 51 w A 1.; J

9 1 a F ZU M Patented Sept. 15, 1931 UNITED FEED BL CROSBY,- OF WORCESTER; MASSACHUSETTS, ASSIGrN-OR T'OwIVEORGA-N' CON-STRUG- TIQN COMPANY, OF VVORGESHZIER, MASSACHUSETTS, A- CORPORATION OF MASSACHU SETTS GAS PRODUCER:

Application fil'd April '29,

The present-invention relates-to pro ducers and more particularlyinvolvesan'ar rangement adapted to automatically secure the intermittent discharge of ashes from the" hottom of the producer during the-gas making operation;

In gas producersof the type-employing-a rotatable ash pan, it has been'customaryto cause ashesto be dischargedfrom the-pro ducer by means'o'f aplow'nor'mally rotatable with the ash pan, but adapted to be held 'sta-' tionary when desired, so as to cause the ashes to-becrowded overthe edge of the flaring sides oftheash'pan; The object ofthe pres ent invention is to p'rovideelectrically operatedmeans for automatically interrupting the normal rotation of the plow' with the 'ash* plan, at predetermined intervals, thereby causing intermittent dischargeof the ashesfrom theb'ottom of theproducer'while it is in" operation, and doing away with the necessity for having an operator to manually "con trol the discharge of ashes, as heretofore.

Mfurther object of 'theinvention is to provide-- means "for readily Varying the length of the time intervals during which the plowis-h'eld-E stationary, Whereby'a greater or less di'sechargeof ashes from theproducer canbe-ei fected' for' a given speedfofoperation: The

Fig. l is anelevation at rightanglesto- Fig. 2.

Figs. 5, 6 and 7' are diagrammatic views illustrating the functioninggof-the electrical-- COHil'Ol-dBVlCGS for different phases ofioperation ofthe mechanism.-

Sis a: diagrammatic view similar to Fig.5 showing the circuit connections for'se s plow b'ei prevented from rotating W 19291 Seri'aTNES. 359,048.

curingcontinuous discharge of ashes during" a complete revolution of the producer,

Fig? 9 is a View similar to Fig. 1 showing the automatic plow control'applied- 'toa dit fcrent typeofproducer. A 5

Like reference characters refer to 4 like" parts -in-the different figures.

Referring to the drawings, there is shown ll'l l lgi'l the lower'portion' of a well know-Ir type of 'p'rodiicer 'providing a gas producing f 6 chamber enclosed within a wall or shell 1" which constitutes the; fuel: supporti'r rgi' sec: tiorr of therprodu'cerz The lower end of the shhlli 1 1' opens 4 into concentric ash support oii--'-pan= Qf proViding 'a horizontal bott'onr b anditfiaring walls 26 'W hlGll surroundand-are spacediiromfitlie shell-1.- The shell 1 is supported from the ash pan '2 by means of *a ce'n trally" disposed casting 8- roviding radial arms fiag only o-n'e' being shown, which serve" 76 the do'uble purpose of 'si'ipporti ng the shell 1 and distributing: the: blast to the fuel becl from the blast passage 4.

The ash' pfan' 2 carrying theshell 1 is *r'o tatably supported on lafmnnber of rollers only one of which is shown, and "rotation is" adapted to beimparted to theenti re producer structure-by means of 'a' pinion'i6 meshing with arrack ea on the underside ofthe ash panQ'. An aslr plow-7 is pivoted 'concentrical-ly With g0 respect "to the rotative' axis of the ash pan 2', i the plowfldying: flat mil-the bottom 2a ofth'e ash pan :so that in the absence of resti aint; the plow 'f is adapted to 1 partake of the ro taryrnrotionimparted to theashpan- 21-" The plow 'z' provides an upwardly inclined pon tion 7a and it is obvious th'at should the retire; ash :pa-n Q, this incl-ined p'ortion 721w tend to: force ashes :upw ard'lyi from' the bottom of 9c the ash pan so' as Eto' be rea dity 'removed bya stationary" skimmer '8 cooperating with the flaring. 1wall oi2theas'h" pan 2".

As bestshownfin'Figs: Qand' 3; the upper end-of the inclined plow portion mterminates iman arm 9 spaced above and projecting overtlie rim of the-ash S pport2'. Rotati'on -of th'eplow 7 with the-part2, in the direction" oi t e-- arrow;isadapted toicarry the projecting-end of the-arm 9%into-engagenrent w itha shoni'clen' ice" i received in a notch 13 provi 10a provided at one end of a pivoted latch 10 which is shown locked against turning so as to hold the plow 7 stationary and cause ashes to be discharged from the producer. The latch 10 is mounted on a shaft 11 supported by a bracket 11a secured to a vertical column 12 of the producer structure and the end of the latch 10 opposite to the low arm 9 is did at one end of a locking lever 14, see Fig. 4. The lever 14 is mounted on a pivot 15 and its other end is connected to a plunger 16 by means of a pin 17. The plunger 16 is movable within a solenoid 18 and when the solenoid 18 is deenergized, as shown, a weight 19 at the lower end of the plunger 16 tends to pull the plunger 16 downwardly and turn the lever 14 in a counterclockwise direction so as to maintain the end of the latch 10 in the notch 13 of the locking lever 14 and prevent turning of the latch 10.

With the parts in the position shown, it is evident that the plow 7 will be prevented from turning with the ash pan 2 by the engagement of its arm 9 with the latch shoulder 10a so long as the opposite end of the latch 10 remains engaged with the locking lever 14. However,'should the solenoid 18 be energized, as will be hereinafter describedwith reference to Fig. 7 the upward movement of the plunger 16 will release the end of the latch 10 from the notch 13. When this occurs, the push of the plow arm 9 on the latch shoulder 10a will turn the latch 10 about its pivot shaft 11 until the shoulder 10a clears the arm 9, whereupon the plow 7 will move with the ash pan 2 and the discharge of ashes from the producer will be interrupted. When the plow arm 9 clears the latch shoulder 10a and passes on, the latch 10 will be returned to its former position with its shoulder 10a in.

the path of movement of the plow arm 9 by means of a weight 20 pulling on a chain 21 passing over a pulley 22 mounted within the column 12, the chain 21 being connected at its other end to the latch 10. Therefore, the weight 20 always exerts a force tending to hold the latch shoulder 10a in position to trip the plow 7, although the pull of the weight 20 itself is not sufiicient to offer any appreciable resistance to turning of the latch 10 by the plow arm 9 when the locking lever 14 is turned to release the end of the latch 10 from the notch 13. In order to cause the plow engaging shoulder 10a of the latch 10 to occupy the proper position, an adjusting stud 23 is provided which is threaded into the latch with its end adapted to bear on the column 12 under the pull of the weight 20, see Fig. 3.

Referring now to Fig. 5, there is shown diagrammatically the electrical devices for automatically controlling the energization of the solenoid 18 so as to release the latch 10 and permit the plow 7 'to rotate with the ash pan r 2. One terminal of the solenoid 18 is permanentl connected to one blade 24 of a knife switc1 25 through a conductor 26, so that when the switch 25 is closed, this terminal of the solenoid 18 is connected to the side of a source 27 of electrical energy. The other terminal of the solenoid 18 is adapted to be connected to the other blade 28 of the switch 25 through a pair of relatively movable and normally open cont-acts 29 of a contactor providing an energizing winding 30. When the winding 30 is deenergized, the contacts 29 are open so that normally the solenoid 18 is in a deenergized condition, as shown in Fig. 5.

One terminal of the winding 30 of the contactor is permanently connected to the blade 28 of the switch 25 so that when the switch 25 is closed, one side of the winding 30 is connected to the side of the source 27. The other terminal of the contactor winding 30 is connected to one stationary contact 31 of a time delay relay generally indicated at 32, the contact 31 being'spaced from a second stationary contact 33 that is permanently connected to the conductor 26 leading from the side of the source 27. The relay 32 provides a pivoted arm 34 which is adapted to bridge the space between the contacts 31 and 33 when the arm 34 is moved into engagement with these contacts under the pull of a solenoid 35. A plunger 36 is movable within the solenoid 35 and the rack and pinion connection indicated between the plunger 36 and the arm 34 is such that an appreciable time interval occurs between the energization of the solenoid 35 and the bridging of the contacts 31 and 33 by the arm 34. This time interval is adjustable, as is usual in time delay relays of this type and one way of obtaining such adjustment is by means of'a set screw 34a which determines the retracted position of the arm 34 under the pull of the spring 34?) which also holds the plunger 36 withdrawn from the solenoid 35. Obviously, other ways of varying the time element could be provided. One terminal of the solenoid 35 of the relay 32is permanently connected to the side of the source through the switch blade 28 while the other terminal thereof is connected to one blade 37 of a three-pole double-throw knife switch 38. When this switch 38 is thrown to its upper position, as shown at Fig. 5, the blade 37 is connected to a stationary contact 39 which is in turn connected to one of a pair of spaced stationary contacts 40. The contacts 40 are adapted to be engaged by a bridging member 41 turnable on a shaft 42 carrying an arm 43, and as shown in Fig. 2', the arm 43 is in the path of movement of a finger 44 projecting from an extension 45 of the arm 9 of the plow which cooperates with the latch 10.

In Fig. 5, the plow arm 9 is indicated as moving with the ash pan 2, in the direction of the arrow, towards the latch 10 which presents its shoulder 10a in the path of move- Leas es? ment of the. arm 9.v Atthis timethe solenoid;- 18'is deenergized, as. are also the conta-etorr winding. 30. and the solenoid 35 of'theetime; delay relay 32. At thiswtime also, while. no;

. aslris. being. discharged from theproducer,

theknife switch 25 has been closedand the. movable blades of the three-pole switch 38: have been thrown to their upper position. forthe purpose of causing; ashes to be discharged-1 from the producer for a predetermined p.e-- riod, as will now be described.

WVhen further rotation of the ash pan 2 car riesthe plow Tfrom the position shown in Fig. 5. to the position shown in-Fig. 6, it is obvious that the latch 10 will preventthe plow from further movement with the ash pan 2, so that immediately following engagement. of the plow arm 9 with the latch 10, the plow 7'starts to discharge ashes. Coincident with the engagement of the plow arm 9-with.the latch.

10, the finger llmovable with the plow en gages the arm 43 on shaft 12, therebyturning the bridging member 41 into engagement withthe spaced contactsiO. WVhen this-occurs, the solenoid 35 of the time delay relay 32 is energized, current then flowing from the side of the source through the-solenoid 35 to the contacts 37 and 39 of the-th ree-pole switch 38 and from thence acrossthe bridged :contacts 410 through the conductor 26 back to the side of the source 27. Theplunger 36" is thereupon drawn within the solenoid 35 to: cause the arm 34: to slowly approach the open contacts 31 and 33, during which time the: ..ashes are being discharged from the pro-- ducer by the stationary plow 7. After the lapse of a predetermined time interval determined by the distance which the end of the arm 34 has to move from its retracted po sition in engagement with its stop. 34a towards contacts 31 ZLIIC 33, bridged. by the arm 3st thereby energizingthe winding 30 of the contactor and closingwits contacts 29. As soon as this occurs, the-plow :locking solenoid 18 will be energized thereby rocking the lever 14 and releasing the end of the latch 10, as shown in Fig. 7. The latch. 10 is then free to turn on its shaft 11 under the push of the plow arm 9, so that the p lowc 7 immediately frees itself from the latch-1O and resumes its rotative movement with the ash pan 2, thereby interrupting the discharge of'ash from the producer, all as indicated in is indicated above, the'period of plowing-,

or sixseconds for the plowing of ash. This is based on the assumption thatthe normal speed of rotation of the produceris one revolution in six minutes, or-360 of turning .in 360: seconds. Since this is at the-rate of 1 per secondand it is assumed that the relay 321.

these contacts will be lS-iSQhiZOnClOSQ thenGOnfaChS:31.111161 33 in six seconds,:.it=.fol:lows; thee plow- 7 will. discharge ash through? 6of'rotation' ofthe ash pan 2. Obviously, ,thegrelay1-32 :can. be set by means of an; adjustable stop,.-3ta-to=. operate; for a greater orless interval than six seconds, which value is assumed merely for the sake o fig-iving an idea of the .mannerin which the plowi functions: to discharge ashes.

Aftertheplow -7 has :freed itself from the latch/l0, and :continues its rotationwith the ash pan'2 for another revolution, the latch 10 is .reset by the. weight .201 and again presents its shoulder 10min theipathllofithe plow arm 9! The love-r 14: also 'resumesr its locking-position'iwi-thzrespect to: thelatch 10, upon: 1 the deenergizationa of lth GSQll lOld 18 which takes place 'aZlJHOSt-"HSrSOOIY-ELS the finger tl releases tire-arm 1. 13-. to-..permit a springacti 11g. :on the. shaft42'to separatebridging member 41 from the contacts 10. When .thisoccurs', the-sole noid; 35 0f the relay 32zis deenergizech whereupon thearm :34 is disengaged from the contacts and=33 to interrupt the circuit of the winding .30 of theicontactor. Upon opening: of the contacts-29,the latch solenoid -18 is'deenergized, thereby permitting the weight 19 to pull the plunger 16"downwardly and move the lELtClII'lGWGI'T14: in position so that theend I of thelatch 10.is again received lEl= tl16i10tCll 13. Therefore,-.as the-plow 7 completes another revolution with .the ash pan'2, after a. lapsevoffaboutwsixminutes, thelatch 10 will.

again: .110161 :the. plowv 7 stationary "and cause the producer'to-x discharge ashes a-second determined intervaliduring: each complete revolution; of theash :pan 2'. This-intermittent discharge of:ashes will. take place entirelyautomatically, so that i no attention is requiredby'an operator.

While theplow' 7 Zis-b'eing held stationary to1cause dischargeof-:ashes, this condition is indiicatedfibythe illumination of red lamp 46 locatedwh'ere it maybe readily observed; 0neiterminal ofthe lampz46 is permanently conneetedctorthe side of the source 27 while the other-terminal is connected to one of; the spaced contacts 10. Consequently, when: the contacts .40; are engaged by'bridg-v ingmember 41 during.- the period thatthe plow 7-is stationary, thelamp ati'will be illua minated: When the plow 7 is released, opens ing:- .-of'the contacts- 10vwill extinguish the lamp andxitiwill =not be' illuminated again until the plow 7 is again held stationary by the latch 10, as olescribed (above.-

In the operation :of a gas producer over timer This second-periodof plowing is the long periods, it is often desirable to have the plow operate so as to discharge ashes for a considerably longer interval than would be possible by adjusting the time delay 'relay 32 for its longest period. That is to say, every six or eight hours it may be desirable to hold the plow stationary for one complete revolution of the producer in order to discharge ashes continuously for that period. For the purpose of causing continuous plowing for the period of one complete revolution only, independently of the intermittent plowing as previously described, the extension 45 carried b the plow arm 9 from which projects the 'nger 44 also carries an insulated contact segment 47. This is adapted to bridge the gap between a pair of spaced insulated contact fingers 48 and 49 carried by a rod 50 supported from the stationary column 12, see Fig. 2. The upper finger 48 is connected to the middle blade 51 of the double throw switch 38 which is adapted to be engaged with stationary contacts 52a and 52b permanently connected to the side of the source 27, in either position of the double throw switch 38. The lower contact finger 49 is permanently connected to a. contact finger 53 also carried by the rod 50, this finger 53 being separated from a second finger 54 except when the gap between them is bridged by an insulated contact segment 55 carried by the producer body 1, see Fig. 2. The contact segments 47 and 55, being carried by the plow 7 and shell 1 respectively, are subject to progressive movement with respect to each other, due to the intermittent movement of the plow 7, so that at regular intervals the segments 47 and 55 will simultaneously bridge the gaps between'fingers 48 and 49 and fingers 53 and 54, see Fig. 6. This position corresponds to what will be termed the zero position of the plow 7 in which it is engaged by the latch 10 at the end of a complete revolution of the producer.

The upper contact finger 54 is connected to the right hand blade 56 of the double-throw switch 38, and when this blade 56 is in the upper position, for causing normal intermittent operation of the plow 7, a circuit is established from the upper stationary switch contact 57 through a green lamp 58 to the side of the source 27. Therefore, both the red lamp 46 and the green lamp 58 are illuminated when the plow 7 is held stationary, as shown in Fig. 6, and the green lamp 58 is extinguished as soon as the segment 55 carried by the shell 1 leaves the lower finger 53, as shown in Fig. 7. However the green lamp 58 will be illuminated only when the switch 38 is in its upper position and when the segment 55 lines up with segment 47 every six hours, under the operating conditions previously assumed.

WVhen it is desired to causecontinuous discharge of ashes for the full 360 of rotation of the producer, the operator waits until the plow 7 is locked under the conditions described above, which condition is indicated by simultaneous illumination of both the red and green lamps 46 and 58. Then as soon as the green lamp 58 is extinguished by the segment 55 leaving the stationary fingers 53 and 54, but before the time delay relay 32 can cause energization of the trip solenoid 18, the operator throws the movable blades of the double-throw switch 38 from the upper position to the lower position, as shown in Fig. 8. WVhen this occurs, the left hand blade 37 is disconnected from the contacts 40 thereby deenergizing the solenoid 35 of the time delay relay 32; consequently the latch 10 will continue to hold the plow 7 stationary while theash pan 2 continues to rotate. Prior to the throw over of the switch 38, rotation of the producer shell 1 with respect to the stationary contact carrying rod 50, has moved the contact segment 55 out of engagement with the fingers 53 and 54 so that when the right hand blade 56 of the switch 38 is moved into engagement with the lower stationary switch contact 59, the direct circuit from contact 59 to the winding 30 of the contactor is incomplete owing to the gap between the contacts 53 and 54.

Bearing in mind the fact that the switch 38 is thrown from its upper position to its lower position in the first few degrees of rotation of the producer shell 1 from its zero position, before the time delay relay 32 can energize the solenoid 18, it is obvious that the plow 7 will remain stationary while the producer is rotating through 360, for during this period there is no way for the solenoid 18 to become energized. However, when the producer completes one revolution with the switch 38 in its lower position for continuous plowing, the contact segment 55 reengages the pair of contact fingers 53 and 54. Since at this moment the other fingers 48 and 49 are bridged by the segment 47 on the then stationary plow, a circuit is established from the side of the source 27 through the middle blade 51 of the switch 38 through all four fingers and their engaged plates 47 and 55 back to the right hand blade 56 of the switch and its contact 59. And since the switch contact 59 is connected directly to one terminal of the contactor winding 30, the circuit through the contactor winding 30 to the -lside of the source 27 is completed independently of the time delay relay contacts 31 and 33. There fore, the solenoid 18 is energized to release the latch 10, holding the plow 7 and the plow 7 automatically resumes its rotation with the producer upon the completion of the full 360 of plowing.

When the producer completes its next revolution with the switch 38 in its lower position, the solenoid 18 will again be energized to release the latch 10, so the plow 7 will continue to rotate withth-e shell 2 and no more plowing will occur whilethe switch 38 is in its lower position. This condition is indicated by momentary illumination of the red lamp 46 for each revolution until.

it has been assumed that the producer shell: and the ash pan rotate in unison in accord ance with the showing of Fig. 1. However,

in the operation of some gas producers, it has been found desirable to rotate the fuel containing shell and the ash pan at slightly different speeds, the purpose of this being to secure a certain amount of shearing effect between the body of incandescent fuel in the shell and the ashes in the pan with result ing agitation of the lower part of the fuel bed. It is within the contemplation of the present invention to provide for the intermittent discharge of ashes from a producer of this modified type and there is shown in Fig. 9 the lower portion of a gas producer of a type in which the shell and the ash pan rotate at different speeds.

In this type of producer, the ash pan 60 is mounted on a ball bearing 61 and is adapted to be rotatably driven by means of a pinion 62- engaging the teeth 63 of a rack on the underside of the ash pan 60. The pinion 62 is mounted on a shaft 64 driven through reduction gearing, not shown, by an electric motor 65. The producer shell 66 is mounted for rotation independently of the ash pan 60 on rollers 67 supporting a ring 68 which also provides gear teeth 69 in mesh with a pinion 70 on a countershaft 71. The shaft 71 is adapted to be driven from the motor 65 through gearing 72 and the gear ratio between the pinion 62 driving the rack 63 on the one hand and the pinion 7O driving the teeth 69 on the other hand is such that for a given speed of rotation of the mo* tor 65, the ash pan 60 will be driven at a slightly greater speed than the shell 66, although in the same direction of rotation. This difference in the rotative speeds is slight, under normal conditions being about only one revolution per hour, so that the shearing action between the incandescent fuel bed in the shell 66 and the ashes in the pan 60 is just enough to give the desired agitation in the lower part of the fuel bed.

A plow 7 is carried by the bottom of the ash pan 60 in substantially the same manner as the plow 7 is carried by the ash pan 2. This plow also provides an arm 9' which projects over the rim of the ash pan 60 and is adapted to cooperate with a: latch 10 under thecontrol of a solenoid 18"in substantially the same manner as described with reference to the plow 7. The arrangement of electrical control devices cooperating with the plow 7 is exactly the same as shown in Fig. 5, withthe exception that the contact 55' in Fig. 9 is carried by the outside of the pan 60 on a bracket- 73, whereas the contact 55 is carried by the shell 1 in Fig. 1. This positioning of the contact 55 necessitates mounting the rod 50 carrying the four contacts 48, L9, 53 and 54 below'the latchlO and the provision of a finger 74 projecting downwardly from the plow arm 9 to-carry the contact 47. In the operation of the modified arrangement of Fig. 9-, the rotation of the pan 60 entirely controls the automatic operation of the plow 7 in'the same manner as described with reference to Fig. 1, so that the slightly lower speed of the shell 66 has no effect on the functioning of the apparatus.

I claim,

1. Ina gas producer, a rotating ash support, an ash removing plow carried by said support, means normally held in the path of said plow to arrest its rotation with said ash support and thereby cause the discharge of ashes from the producer, and automatic means set in operation upon the arrival of said plow in its arrestedposition for causing said plow arresting means to release said plow after ashes have been discharged from said producer for a predetermined interval.

2. In a gas producer, a rotating ash support, an ash removing'plow carried'by said support, means normally held in the path of. said plow to arrest its rotation with said ash support and thereby cause the discharge ofashes from theproducer, means set in op eration upon the arrival of said plow in its arrested position for automatically releasing said plow from said plow arresting means afterva predetermined interval, and means for restoring said plow arresting means to its inltial position, whereby said plow effects the delivery of ashes from said producer at reg-' 1n the rotation ul'ar predetermined intervals of said ash support.

3. In a gas producer, a rotating ash support, an ash removing plow carried by said? support, means normally held in the path ofsaid plow to arrest its rotation with said ash support and thereby cause the discharge of ashes from the producer, and electricallyoperated means comprising a time delay relay device adapted to be energized upon the arrival of said plow in itsarrested position for automatically causing the said plow arresting means to release said predetermined; interval.

4. In a gas producer, the combination with a rotating ash-support and an ash removing plow. carriedby said support and adapted to plow after a normally rotate therewith, said plow provid ing a portion extending upwardly through the ash bed and projecting outside of said support, of a latch member disposed in the path of movement of the projecting portion of said plow to prevent rotation thereof with said support, and an electrically-operated means controlled by the arrival of said plow for releasing said plow in its locked position after it has been held stationary a predetermined interval.

5. In a gas producer, the combination with a rotating ash support and an ash removing plow carried by said support and adapted to normally rotate therewith, said plow providing a portion extending upwardly through the ash bed and projecting outside of said support, of a latch disposed in the path of movement of the projecting portion of said plow with said ash support for preventing movement thereof, a solenoid for controlling said latch, and a circuit controller actuated by the movement of said plow for energizing said solenoid a predetermined interval after the arrival of said plow in its locked position for releasing said plow from said latch to cause its rotation with said ash support.

6. In a gas producer, the combination with a rotating ash support and an ash removing plow carried by said support and adapted to normally rotate therewith, said plow providing a portion extending upwardly through the ash bed and projecting outside of said support of a pivotally mounted latch disposed in the path of movement of the project ing portion of said plow with said ash support, means for preventing pivotal movement of said latch by said plow to thereby lock said plow against rotation with said ash support, and adjustable time delay means set in operation by the arrival of said plow in its locked position for automatically releasing said latch to cause said plow to resume rotation with said ash support after ashes have been discharged from said producer over a predetermined interval.

7. In a gas producer, the combination with a rotating ash support and an ash removing plow carried by said support and adapted to normally rotate therewith, said plow providing a portion extending upwardly through the ash bed and projecting outside of said support, of a latch disposed in the path of movement of the projecting portion of said plow with said ash support, means for looking said latch against pivotal movement to prevent rotation of said plow, a solenoid for controlling the operation of said latch locking means, and an' adjustable time delay switch controlled by the arrival of said plow in its locked position for automatically energizing said solenoid to release said latch after ashes have been discharged from said producer during a predetermined interval.

8. In a gas producer, the combination with tion, and circuit controlling devices set inv operation upon the engagement of said plow with said-latch for automatically energizing said solenoid to release said latch and permit said plow to rotate with said ash support after ashes have been discharged by said producer during a predetermined interval.

FRED B. CROSBY. 

